Recording device for rotatable mixers

ABSTRACT

A counter system including a magnetically actuatable switch housed in a protective case. The case is secured to a frame supporting a rotatable mixing drum. A magnetic actuator is resiliently mounted on the drum and is moved past and close to the switch at each drum revolution. The switch is connected through an electrical circuit to a counter so that total revolutions of the drum are measured. A second counter system measures both total and mixing speed revolutions of the drum. In this second system one counter is actuable only if the drum is turning at a preselected speed. Two switches are used and they are connected to an electrical circuit which provides a signal to the mixing counter only if the drum is turning at mixing speed.

United States Patent [72] Inventor Audry R. Kinney 231 Belmont Terrace, Mount Vernon, Wash. 98273 [21] Appl. No. 753,674 [22] Filed Aug. 19, 1968 [45] Patented June 1, 1971 [54] RECORDING DEVICE FOR ROTATABLE MlXERS 11 Claims, 5 Drawing Figs.

[52] US. Cl 235/92, 235/ 103 [51] Int. Cl G06f 7/38 [50] Field of Search 235/92, 103; 317/147, 148.5; 324/68, 70; 340/168; 335/205--7 [56] References Cited UNlTED STATESPATENTS 3,219,804 11/1965 Annable 235/92 3,277,284 10/1966 Cripe et al. 235/92 3,467,821 9/1969 Arp 3,496,343 2/1970 Johanson ABSTRACT: A counter system including a magnetically actuatable switch housed in a protective case. The case is secured to a frame supporting a rotatable mixing drum. A magnetic actuator is resiliently mounted on the drum and is moved past and close to the switch at each drum revolution. The switch is connected through an electrical circuit to a counter so that total revolutions of the drum are measured. A second counter system measures both total and mixing speed revolutions of the drum. In this second system one counter is actuable only if the drum is turning at a preselected speed. Two switches are used and they are connected to an electrical circuit which provides a signal to the mixing counter only if the drum is turning at mixing speed.

PATENTEIJ JUN 1 I97! SHEET 1 BF 2 AUDRY R. KINNEY INVENTOR. 4

BY gaw M m I ATTORNEYS BACKGROUND OF INVENTION 1. Field of the Invention This invention pertains to devices for measuring revolutions of concrete mixing drums and in particular to devices for measuring total revolutions, or both total and agitating speed revolutions.

2. Description of the Prior Art Counters for recording the revolutions of mixing drums have become of increasing importance particularly on transitmixer trucks for carrying concrete. In some areas of the country these trucks may be used only if the total number of revolutions of the drum for each batch of concrete is recorded. In other areas of the country not only must total revolutions be counted but mixing speed revolutions must also be recorded.

Some of the prior drum revolutions recorders have been of the mechanical type. In general such mechanical recorders are expensive to manufacture and are highly susceptible to damage or malfunction in adverse environmental conditions, such as concrete dust, mud, water, etc. likely to be present around the concrete loading and pouring sites. Other recorders have been of the electrical type but these have also been complex and accordingly expensive to manufacture and have heretofore been easily damaged or susceptible to malfunctions in adverse environments. The difficulties experienced with heretofore known electrical counters have generally been caused by caking of the mud, etc. in the switch elements or damage to the switch elements by truck vibration or by misalignment of the switch actuator fixed to the drum.

SUMMARY OF THE INVENTION This invention pertains to counters of the electrical type that may be used for counting revolutions of drum mixers for concrete either of the stationary mounted type or, preferably, of the transit-mixer-type. A counter for measuring total revolutions or a counter for measuring at or above mixing speed revolutions may be used. Also a dual counter system may be used for recording total and mixing speed revolutions. The circuitry and components forming the invention are uniquely simple thus making them inexpensive to manufacture. Their simplicity also precludes the need for trained electronics experts for maintenance in the field.

In addition the switch means exposed to the concrete dust, mud and water prevalent in the environment around concrete loading and pouring sites are uniquely shielded and are shock resistant to reduce malfunctions under these adverse conditions. Still another feature is a unique manner of flexible mounting the switch actuator to the rotatable mixing drum so as to avoid damage to the switch means when the drum and truck frame are moved relative to each other under the weight of the concrete load.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view of a transit-mix concrete truck carrying a recording device made according to the invention;

FIG. 2 is a fragmentary isometric view of a portion of the truck encircled by the line 2 in FIG. 1 and showing, in particular, the positions of the switch and switch actuator;

FIG. 3 is a circuit diagram of a total revolution counter device including an enlarged cross section view of the switch means and case used in the circuits; and

FIG. 4 is a circuit diagram of another form of counter device that includes a total revolution counter and a mixing speed revolution counter.

FIG. 5 is a diagrammatic view ofa modified form of recording system.

DESCRIPTION OF PREFERRED EMBODIMENTS A transit-mix concrete truck is best shown in FIG. 1 and includes a rotatable mixing drum 12 supported by a forward bearing support 14 and a rear bearing support, not shown. The drum is rotated by a drive sprocket l6 driven by a chain 18 (FIG. 2). The truck illustrated is of conventional construction. In the alternative a truck employing rotating mixing blades within the drum rather than a rotating drum may also be used. In either form the drum or blades will have a direction of mixing rotation as indicated by the arrow 19.

In accordance with the invention switch means 20 (FIG. 2)

is secured to the forward bearing support. The switch means 20 is electrically connected to a total revolutions counter 26 that measures total revolutions of the drum. The switch means 20, as is best shown in FIG. 3, comprises a conventional reed switch 30 housed in a bore 32 of a cylindrical tube 34. The tube may be of any suitable high strength material, such as aluminum, steel or plastic. The reed switch is embedded in a sealant, such as plastic 36 which is allowed to harden within the bore. Thus, the contacts 30a and 30b of the reed switch 30 are not only protected from moisture but are shielded by thev plastic from shock and other adverse environmental conditions. The cylindrical tube 34 is secured to a mounting block 38 (FIG. 2) which is fastened to one leg of an angle bracket 40. The other leg of the angle bracket is secured to a mounting.

bar magnet 46 secured in a nonporous metal or plastic case 48. The case is fastened to a rubber or flexible strip 50 releasably secured in a mounting bracket 52 fastened to the sprocket by any suitable means. Preferably, the magnet is aligned along a radial plane of the drum so that the longitudinal axis of reed switch 30 and the magnet are parallel as the magnet passes the switch. An important aspect of the switch actuator is that the rubber strip provides excellent flexibility so that it may yield to avoid damage to the switch means if they collide. Such a collision may otherwise be possible, for example, when the drum is heavily loaded and the transporter vehicle is traversing rough terrain to twist the truck chassis and force the switch and actuator out of alignment.

The circuit for the single counter device is shown in FIG. 3. Contacts 30a and 30b of reed switch 30 are biased open as is well known are closed when a magnetic field passes closely adjacent to them. A conductor 54 connects the contact 30a to a terminal 55 of a junction box, not shown, mounted on the truck. The terminal 55 is connected through a conductor 56, a

fuse 57, and a conductor 58 to the truck battery or electrical system 59. A conductor 60 connects the battery to another I conductor to an on-off switch 66. The on-off switch,

through a conductor 67, is connected to a terminal 68 and then through a conductor 69 to another terminal on the total revolution counter.

After the on-off switch 66, which may be key operated to prevent tampering, is closed a revolution is counted each time magnet 46 of the switch actuator 44 passes the reed switch of switch means 20. As the magnet passes the reed switch 30 the contacts 30a and 30b are closed and the circuit is completed. Accordingly, the counter 26 is energized to register the revolution regardless of drum speed. The total revolution counter 26 adds the revolutions showing total turns made by the drum and will be reset to zero each time the vehicle leaves the plant with a new load. The counter is reset or zeroed by a conventional reset button or knob on the counter. Although not shown, antitampering locks or other devices may be used on the counter or junction box to assure the count registered indicates the actual number of revolutions made by the drum between the concrete loading and discharge points.

The dual total and mixing speed counter system, in the alternative form of the invention, includes a second switch means 24, identical to switch means 20, secured to the forward bearing support 14 on the right-hand side of the truck. ln other words, second switch means 24 is angularly spaced in the direction of mixing rotation (arrow 19) from the switch means 20. The exact spacing is not critical but is related to the components of the circuit. The switch means is also in the form of a reed switch 35 having contacts 35a and 35b connected to a circuit having mixer speed counter 28. Both in a single counter form and the modified form the counters are preferably mounted in the cab of the vehicle within sight of the driver.

FIG. 4 shows the circuit diagram for the dual counter system. First switch means 20 is shown again and includes reed switch 30 having contacts 30a and 30b. For clarity different reference numerals will be used hereinafter for the conductors connected to these contacts 300 and 30b to distinguish this circuit from the single counter circuit described above. A conductor 70 connects the contact 30a through a fuse 71, a conductor 72, an on-oif switch 73 and a conductor 74 to the truck battery or electrical system 75. Of course the fuse, on-off switch and battery will be the same as used for the single counted but again for clarity will be described with different reference numerals. A conductor 76 connects one side of the battery to a relay 78 having two sets of contacts 80 and 81. Contacts 80 are connected to a conductor 82 which connects with contact 30b of the reed switch 30 through a conductor 84. Contacts 80 are also connected to a terminal of the total counter 26 through a conductor 85. The other terminal of the total counter 26 is connected to the conductor 78 through a conductor 87. As thus far described, when the contacts 30a and 30b and the on-off switch 73 are closed a pulse will be sent to the total counter 26 to register a revolution as above.

The remainder of the circuit in H0. 4, now to be described, provides for counting only those drum revolutions at a preselected speed. As shown, conductor 82 is also connected to the relay contacts 81. One of the contacts is connected through a conductor 90 to the contact 350 of the reed switch 35. Connected between the conductor 90 and the conductor 76 by a pair of conductors 91 and 92 is a mid. capacitor 94. Contact 35b of the reed switch 35 is connected by a conductor 95 to one terminal of mixing speed counter 28. The other terminal of the mixing speed counter is connected by a conductor 96 to conductor 76. Connected between the contact 35a and the terminal of the mixing speed counter to which the conductor 95 is connected are a variable control resistance 98 and a variable trim resistance 99.

The circuit for mixing speed counter 28 is operated partially by the pulse obtained when contacts 300 and 30b of reed switch 30 are closed to charge the capacitor 94. The variable resistances 98 and 99 will slowly drain the charge of capacitor 94 during the interval between the time the first switch means 20 is closed and the second switch means 24 is closed. In other words, if the drum is turning very slowly a long period of time will elapse between the time the magnetic actuator 44 will traverse the distance between the first and second switch means 20 and 24. Depending upon the setting of the variable resistance this time will be sufficient to drain substantially all of the charge from the capacitor 94. Thus, when the magnetic actuator closes the contacts 35a and 35b of the reed switch 35 there will be insufficient charge left in the capacitor 94 to energize the mixing speed counter 28. It should be noted at this point that the mixing speed counter 28 is only actuated when the voltage is above a predetermined level. Since legal requirements normally set an acceptable mixing speed between about 4 and i2 revolutions per minute, the drum speed can be selected and counter 28 will record at or above the selected speed.

If the drum 12 is rotated at or above the desired speed as determined by the settings on the resistances 98 and 99, there will be insufficient time between the closing of the contacts 30a and 30b and the contacts 30a and 30b for the capacitor 94 to be drained of much of its charge. Consequently, when the contacts 35a and 35b are closed the voltage will be of sufficient magnitude to actuate counter 28.

An alternative form of circuit for the at or above mixing speed counter shown in FIG. 4 is indicated by a dotted line conductor 100 between the conductor and the conductor 85 and by connecting conductor 87 to line 84 at point 102 rather than to line 76 through line 104. This conductor may be used in lieu of the relay and relay contacts to produce a less expensive circuit. Normally, however, the relays will be kept in the circuit since sparking will occur between the contacts 35a and 35b of the actuator switch 35 and unless a spark suppression type of switch is used, otherwise recording of the mixing speed counter 28 may be erroneous.

An important feature of the invention is that the mixing speed setting may be raised above the minimum required by the state or other specifications to enable best usage of the truck and driver. For example, if the distance between the loading and pouring sites is known to be short the setting required to record a revolution at mixing speed may be raised thereby showing the driver that he must speed up the drum to obtain a recording of the number of revolutions at mixing speed and, of course, above the state required minimum speed. The correct number of revolutions above the state required minimum speed will thus be obtained by the time the truck arrives at the pouring site.

Another modification is shown in H6. 5 and employs two magnets 44a and 44b circumferentially and radially spaced on the mixing drum 12a rather than circumferentially spacing the switch means 20. Thus, the time delay actuation of the switches is still accomplished. By using two axially aligned switch means 200 and 20b fastened to the forward bearing support 14a, each magnet can separately actuate the switch means with which it is aligned. By using two magnets the same measurement of total mixing speed revolutions is obtained.

Obviously, the above illustrations are by way of example only, as the invention is capable of being expressed in many varying modifications readily apparent to those skilled in the art. Therefore the invention is to be limited only by the scope of the appended claims.

What I claim is:

1. In combination with rotatable structure mounted on supporting frame means, the improvements for recording conditions with respect to said rotatable structure comprising:

a. switch means mounted on said supporting frame means adjacent said rotatable structure, said switch means being encased in a shock and weather resistant housing, a tubular housing and fill material therein in which said switch means is embedded;

b. at least one electrically operated counter for recording revolutions of said rotatable structure;

c. nontiming circuit means connecting said switch means and said counter; and

d. switch actuator means flexibly mounted on said rotatable structure for movement past and in close proximity to said switch means upon rotation of said rotatable structure, so that if said actuator means contacts said housing the actuator will flex and continue to move with said rotatable structure.

2. The combination according to claim 1, wherein said switch means is magnetically actuatable and wherein said switch actuator means includes a magnet secured to said flexible mounting for actuating said switch means.

3. The combination according to claim 2, wherein said switch means is a magnetically operated reed switch.

4. In combination with rotatable structure mounted on supporting frame means, the improvements for recording conditions with respect to said rotatable structure comprising:

a. first and second switch means mounted on said supporting frame means adjacent said rotatable structure and being encased in shock and weather resistant housings;

. first electrically actuated means for counting total rotatable structure revolutions;

c. second electrically actuated means for counting rotatable structure revolutions at preselected speeds within a predetermined speed range;

at least one actuator means flexibly secured to said rotatable structure for movement past said first and second switch means and closely adjacent thereto for independent preselected time interval actuation of said switch means upon rotation of said rotatable structure; and

e. circuit means electrically interposed between said first and second switch means and said first and second counting means, wherein said circuit means energized said second switch means upon movement of said rotatable structure within said predetermined speed range.

5. The combination according to claim 4, wherein said first and second switch means are in circumferentially spaced relation to one another.

6. The combination according to claim 5, wherein said second counting means is actuatable only above a preset voltage in said circuit means.

7. The combination according to claim 5, wherein said circuit means includes a capacitance and variable resistance, said capacitance being charged upon actuation of said first switch means and slowly discharged by said variable resistance, so that the time interval between actuation of said first switch means and said second switch means will determine the amount of voltage remaining to actuate said second counting means.

8. The combination according to claim 4, wherein said first and second switch means are magnetically operated reed switches.

9. The combination according to claim 4 and wherein said at least one actuator means is flexibly mounted on said rotatable structure.

10. The combination according to claim 9 and wherein there are two spaced-apart switch actuating means for actuating said first and second switch means.

11. The combination according to claim 10, wherein said first and second switch means are in close proximity to each other on said supporting frame means. 

1. In combination with rotatable structure mounted on supporting frame means, the improvements for recording conditions with respect to said rotatable structure comprising: a. switch means mounted on said supporting frame means adjacent said rotatable structure, said switch means being encased in a shock and weather resistant housing, a tubular housing and fill material therein in which said switch means is embedded; b. at least one electrically operated counter for recording revolutions of said rotatable structure; c. nontiming circuit means connecting said switch means and said counter; and d. switch actuator means flexibly mounted on said rotatable structure for movement past and in close proximity to said switch means upon rotation of said rotatable structure, so that if said actuator means contacts said housing the actuator will flex and continue to move with said rotatable structure.
 2. The combination according to claim 1, wherein said switch means is magnetically actuatable and wherein said switch actuator means includes a magnet secured to said flexible mounting for actuating said switch means.
 3. The combination according to claim 2, wherein said switch means is a magnetically operated reed switch.
 4. In combination with rotatable structure mounted on supporting frame means, the improvements for recording conditions with respect to said rotatable structure comprising: a. first and second switch means mounted on said supporting frame means adjacent said rotatable structure and being encased in shock and weather resistant housings; b. first electrically actuated means for counting total rotatable structure revolutions; c. second electrically actuated means for counting rotatable structure revolutions at preselected speeds within a predetermined speed range; d. at least one actuator means flexibly secured to said rotatable structure for movement past said first and second switch means and closely adjacent thereto for independent preselected time interval actuation of said switch means upon rotation of said rotatable structure; and e. circuit means electrically interposed between said first and second switch means and said first and second counting means, wherein said circuit means energized said second switch means upon movement of said rotatable structure within said predetermined speed range.
 5. The combination according to claim 4, wherein said first and second switch means are in circumferentially spaced relation to one another.
 6. The combination according to claim 5, wherein said second counting means is actuatable only above a preset voltage in said circuit means.
 7. The combination according to claim 5, wherein said circuit means includes a capacitance and variable resistance, said capacitance being charged upon actuation of said first switch means and slowly discharged by said variable resistance, so that the time interval between actuation of said first switch means and said second switch means will determine the amount of voltage remaining to actuate said second counting means.
 8. The combination according to claim 4, wherein said first and second switch means are magnetically operated reed switches.
 9. The combination according to claim 4 and wherein said at least one actuator means is flexibly mounted on said rotatable structure.
 10. The combination according to claim 9 and wherein there are two spaced-apart switch actuating means for actuating said first and second switch means.
 11. The combination according to claim 10, wherein said first and second switch means are in close proximity to each other on said supporting frame means. 